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It sounds like you saw a couple seizures last night. They don't sound like full grand mal seizures, but potentially partial seizures. This will lead to muscle tremors, decreased responsiveness and incontinence. Seizures usually only last 30-60 seconds, followed by a post-ictal period of anxiety and restlessness that can last minutes to hours.
In an older dog, the most common cause of seizures is a brain tumor. In a younger dog 1-5 years of age the most common cause is epilepsy.
I would get some bloodwork to rule out electrolyte abnormalities as the cause. From there, you could go the wait and see approach or just go get an MRI of the head to rule out brain tumors. I usually go the wait and see to determine if the MRI is necessary.
Here is a nice handout on seizures in dogs:
I hope this helps, let me know if you have any other questions.